Vertical broaching machine



Oct. 14, 1969 J. K. FULKs VERTICAL BROACHING MACHINE Filed May 26. 19673 Sheets-Sheet l ATTORNEYS Oct. 14, 1969 J. K. FULKS VERTICAL BROACHINGMACHINE 3 Sheets-Sheet 2 Filed May 26. 1967 FIG. 2

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ATTGRNEYS Oct. 14, 1969 J. K. FULKs VERTICAL BROACHING MACHINE 3Sheets-Sheet 3 Filed May 26. 1967 mvENToR A4 Fa/.Afs

lav/4b, 74m., Mf''v/f JAMES ATTORNEYS United States Patent O 3,472,123VERTICAL BROACHING MACHINE James K. Fulks, Detroit, Mich., assignor toColonial Broach & Machine Company, Warren, Mich., a corporation ofDelaware Filed May 26, 1967, Ser. No. 641,533 Int. Cl. B23d 37/00 U.S.Cl. 90--95 8 lClaims ABSTRACT F THE DISCLOSURE A vertical broachingmachine having a pair of balanced broach handling fixtures arranged toreciprocate between downward cutting and upward return strokes. Thefixtures have drive rams which are interconnected by a common drivepinion. Rotation of the pinion simultaneously raises one xture in anon-cutting return stroke while driving the companion fixture in adownward cutting stroke.

Machines for broaching internal and external surfaces are disclosed.

A track and carriage arrangement mounted on the frame of the externalbroaching machine provides means for moving the broaching tool from itshandling fixture above the work station to a lateral position forreplacement.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to broaching machines and more specifically to a verticalbroaching machine having a pair of broach handling fixtures which arereciprocated in opposite directions through their cutting and returnstrokes by a common drive pinion.

Description of the prior art Broach handling fixtures of vertical broachmachines are conventionally mounted for movement between raised andlowered positions and include upper and lower broach handling fixturesand a drive ram member connected to a reversing drive system. The drivesystem is arranged so that an elongated broaching tool carried by theupper and lower handling fixtures is reciprocated between a cuttingstroke in one vertical direction wherein it performs a surface-finishingoperation on a workpiece and a non-cutting return stroke in the oppositevertical direction.

Rack and pinion drive systems are normally employed to produce precisionwork with very close tolerances. Conventionally the rack forms a part ofthe drive ram and with the drive pinion connected to reversing drivemeans and meshed with the rack. When the pinion is rotated in onedirection, the handling fixtures and broaching tool are raised. Reversedrotation of the pinion lowers the handling fixtures and the broachingtool.

A drawback with conventional broaching machines employing a rack andpinion system for reciprocation of the broaching tool, the ram and thebroach handling fixtures is that the massive weight of these componentsrequires that the drive means deliver a very high torque through thedrive pinion to raise the broaching tool and its associated movingcomponents to their uppermost position.

It is the broad pfurpose of the present invention to provide a pair ofcounterbalanced vertically mounted broach handling fixtures driven by acommon drive Pinion arranged to reciprocate the fixtures in oppositedirections so that the energy required to raise one handling fixture andits tool in an upward stroke is supplied by the release of the potentialenergy of the companion broach handling fixture and its tool descendingin a downward stroke.

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SUMMARY oF THE INVENTION The preferred embodiment of the presentinvention, which will subsequently be described in greater detail, takesthe form of a base supporting an upright frame having a pair of spacedapart vertical guideways. Each guideway is associated with a workpiecesupporting fixture mounted on the base. An upper broach handling fixtureis mounted for an up and down movement in each of the gruideways. A ram,connected to each upper handling xture, supports a broach pullingmechanism arranged to engage the leading end of an internal broachingtool moving? in a downward cutting stroke after its leading end hasdescended through the rough finished hole of the workpiece.

Each ram has a vertical drive rack meshed with a common drive pinionconnected to a reversing drive means. When the pinion is rotated in afirst direction, one of the drive rams is raised in a non-cutting strokewhile the opposite `drive ram is driven downwardly with its broach insurface-finishing engagement with the workpiece. At the completion of acutting stroke, the cycle is reversed with the pinion rotated in theopposite direction so that the lower drive ram and its broaching toolare returned to their raised position while the upper drive ram and itstool are driven downwardly in the cutting stroke.

It can be seen that a broach handling fixture and its tool disposed intheir raised position possess potential energy because of theirposition. As the handling fixture and its tool descend from their raisedposition, this potential energy of position is transferred throughkinetic energy to the interconnected upwardly moving handling fixtureand tool. This counterbalanced arrangement reduces the required powerinput to the machine to that which is necessary to perform the actualwork of cutting the workpiece.

An alternative embodiment of the invention employs a paii of externalsurface broaching tools arranged to reciprocate between upward returnstrokes and downward cutting strokes with the two broaching tools drivenin opposite directions by a common drive pinion.

It is ldiflicult procedure to replace an extern-al broaching toollmounted in its 4raised working position on the broaching machine. Thereasons are two-fold. First, external broaching tools characteristicallyhave a substantial weight. Secondly, :at the end of its return stroke,the tool is in a raised position above the work platen and 'variousworkpiece Ilocating fixtures which interfere with the replacementactivity. Tool transfer means are therefore provided in the alternativeembodiment of the invention for readily transferring the broaching toolyfrom its normal position Iat the work station and Iabove the workplaten to :a lateral position where the broaching tool clears the workstation and i-s `readily accessible yfor hand'lin g 'and replacement.

The tool transfer means comprises a horizontal track mounted to the`frame of the machine above the raised position of the tool and acarriage mounted on the track. The carriage is movable between a firstposition labove the work station wherein a set of chucks engage thebroaching tool and :a second position horizontally spaced from the workstation Where the broaching tool is readily accessible to the operatorand lowered from its raised position.

It is therefore an object of the present invention to provide animproved vertical broaching machine having a pair of -reciprocallymounted broach Ihandling fixtures interconnected by ya common `dr-ivingelement arranged to move one of the broach handling fixtures in acutting stroke While moving the companion handling fixture unit in areturn stroke.

It is another object of the present invention to provide a verticalbroaching machine having a pair of individual broach handling fixturesmounted for reciprocal vertical movement and driven by a reversing drivemeans through a common drive pinion arranged so that rotation of thedrive pinion in a first `direction raises one of the broach handlingfixtures and its tool while lowering the companion broach handlingfixture and its tool, rotation of the drive pinion in a reversedirection lowers the raised broach handling fixture and tool and raisesthe companion broach handling fixture and tool.

It is a still further object of the present invention to provide avertical broaching machine having a pair of counterbalanced broachhandling fixtures having a similar weight which are mounted `forreciprocal up and down movement between raised and lowered positions anddriven by a common drive pinion arranged so that the potential energy ofone broach handling Ifixture descending from its 4raised position istransferred through the drive pinion to the opposite broach handlingfixture ascending from its lower position.

`It is another object of the present invention to provide a tooltransfer means for a vertical broaching machine including la trackmounted to the frame of the broaching machine, a carriage movablymounted on the track between a first position adjacent the work stationand a second station laterally spaced from the work station and chuckmeans carried by the carriage for engaging the broaching tool at thework station so that the tool can be moved by the carriage from the workstation to the second station.

Still further objects Iand advantages of the present invention willreadily occur to one skilled in the art to which the invention pertainsupon reference to the following description DESCRIPTION OF THE DRAWINGSThe description refers to the accompanying drawings in which likereference characters refer to like parts throughout the several viewsand in which:

FIG. 1 is a perspective view of a vertical internal broaching machineillustrating a preferred embodiment of the present invention;

FIG. 2 is a schematic view of the broaching machine of FIG. 1illustrating the interconnecting drive arrangement between the pair ofreciprocating broach handling fixtures and with the workpiece handlingfixtures removed for purposes of clarify;

FIG. 3 is a schematic view illustrating the drive system of the machineillustrated in FIG. l;

FIG. 4 illustrates a vertical broaching machine for finishing externalsurfaces and illustrating another embodiment of the invention;

lFIG. 5 is a schematic view illustrating the drive system of the machineof FIG. 4; and

fFIG. 6 is a schematic view illustrating the broach transfer meansmounted on the machine of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings,FIGS. 1-3 illustrate a preferred vertical broaching machine 10 having apair of work stations 12 and 14. The broaching machine 10 comprises apair of broach handling fixtures 16 land 18 associated with workstations 12 and 14 respectively and mounted for reciprocal up and downmovement on an upright frame 20. Broach handling fixtures 16 and 18 aredriven by a drive system 22.

`For purposes of description, work stations 12 and 14 `are similar toone another as are broach handling fixtures 16 and 18 with the drivesystem 22 being arranged to lower one of the broach handling fixtures ina cutting stroke while simultaneously raising the opposite broachhandling fixture in a return stroke and then to alternate this motion.

The frame 20 is supported by a pair of lateral base portions 23. Aplaten 24 `forms a part of each base portion 23 and is associated witheach of the work stations 12 and 14. A workpiece supporting fixture 26is mounted on each platen 24 and supports and locates a workpiece 28having 'a rough-finished internal hole which is to be finished by aconventional elongated, tapered broaching tool 30. The broaching tools30 are supported by the broach handling fixtures 16 and 18.

For purposes of the description the machine 10 is described withreference to `a pull-down type of machine wherein the broaching tool 30descends from a raised position until its lower end is received by theopening in the workpiece 28 which is to be finished and then is engagedby a broach pulling mechanism. The broach pulling mechanism pulls thebroaching tool downwardly so that the cutting edges of the broachingtool engages the surface of the workpiece in a surface-finishingrelationship. At the end of the cutting stroke, the finished workpieceis removed, the broach handling fixture `and the broaching tool areraised to their upper position wherein they lare spaced above the platen24 to permit positioning of the succeeding workpiece by the fixture 26.

The broach handling fixtures 16 and 18, as hereintofore mentioned, aresimilar and each includes an upper handling slide 32 mounted for guidedup and down movement in a pair of spaced apart vertical iguideways 34. Abracket 36 extends outwardly from each of the slides 32 and carries abroach supporting fixture 38. The broach supporting fixture 38 includesa conventional chuck 40 adapted to engage the upper end of the broachingtool 30.

The yframe 20 has a bracket 42 fixed above the raised position of eachof the brackets 36. A fixture 44, mounted on each :bracket 42 andpreferably comprising a ball screw arrangement receives a lead bar 46having a continuous helical thread. The lower end of the lead lbar 46 isengaged by the fixture 38 so that the lead bar 46 moves up and 'down asa unit with its associated lbroach handling fixture. As the lead bar 46`advances through the fixture 44 in its downward stroke it rotates andin turn causes the chuck 40 and the broaching tool 30 to rotate in theirdownward cutting stroke. This arrangement has particular ladvantages inachieving a finished internal helical surface in the workpiece 28. Thelead bar 46 can be disconnected from the fixture 38 when the broachingtool 30 is not intended to rotate.

The upper end of the lead bar 46 is received by a guide fixture 48mounted on frame 20 which functions to stabilize the upper free end ofthe lead bar 46 in the raised position of its broach handling fixture.

A hydraulic cylinder 50 fixed to each of the handling sli'des 32provides means .for moving each handling slide independently of itsdrive ram member 54. A link 52 provides a connection between eachhandling, slide 32 and its drive ram 54. The rams 54 are also slidablysupported in the guideways 34 so that each upper handling slide 32 andits ram 54 move up and down as a unit during a major portion of theircutting and return strokes.

A broach pulling mechanism 56. FIG. 2, is carried at the lower end ofeach ram S4 and has a broach pulling chuck 58 aligned with the chuck 40carried by each upper handling slide 32. It can be seen that the chucks40 and 58 are vertically spaced apart from one another a sufficientdistance to accommodate the broaching tool. Preferably means (not shown)are provided for adjusting the distance between the rams 54 and theupper handling slides 32 to accommodate broaching tools of differentlengths.

Each of lthe rams 54 has a drive rack 60. The drive racks 60 aredisposed in a spaced apart opposed relationship and meshed with a drivepinion 62. The drive pinion 62 is supported yfor rotation about ahorizontal axis by the iframe 20 and, as best seen in FIG. 3, is driventhrough a reduction gear unit 63 by a variable speed, reversing motor64. When the motor rotates the pinion 62 in a clockwise direction asviewed in FIG. 2, the broach handling fixture 16 moves in a downwardcutting stroke and the breach handling fixture 18 moves upwardly in areturn stroke. At the end of the cutting stroke of the breach lhandlingfixture runit 16, and upon reversal of the output of the motor 64, thepinion 62 rotates in a counterclockwise direction so that the breachhandling fixture 16 is raised in a return stroke and the companionbroachhandling fixture 18 is driven `downwardly in a cutting stroke.

The complete werk cycle of each breach handling fixture is bestillustrated in FIG. 2. The upper Ihandling slide 32, the Ibreaching tool30 and the ram 54 move in a downward cutting stroke Iuntil stop means(not shown) terminate the downward movement ef the upper handling slide32 as the upper end of the breaching tool 30 approaches the workipiece28.

'Ilhe upper end of the breaching tool 30 is disconnected from the chuck40 so that the ram 54 and the breaching tool 30 continue downwardlyindependently of the upper handling slide 32 with the -free upper end ofthe breaching tool 30 passing through the finished fhole in theworkpiece 28. The finished workpiece is then removed from the platen 24.

Each ram 54 commences its upward return stroke independently of theupper handling slide 32 until the free upper end of the breaching tool30 has been received by the chuck 40. The ram 54 and upper handlingslide 32 continue their return stroke as a unit with the breaching tool30. At the end of the return stroke of the ram 54 the chuck 58 isdisconnected from the lower en-d orf the breaching tool 30 the upperhandling slide 32 and the breaching 'tool 30 continue upwardly undercontrol of the hydraulic cylinder 50 and independently of the ram 54until the lower end of the breaching tool is spaced above the platen 24.An iunfinished workpiece is `mounted in the workpiece supporting fixture26. 'Ihe upper handling slide 32 commences its downward movementindependently of the ram 54 until the lower end of the breaching tool 30has been received ib-y the unfinished workpiece 28 and eugaged by thepulling chuck 58. Tlhe upper handling slide 32, the breaching tool 30and the ram 54 then continue downward in a cutting stroke.

It can be seen that because of the symmetrical mounting arrangementofthe breach handling fixtures 16 and 18, the weight e-f these fixturesland their breaching tools 30 move in a counterbalanced relationship sothat the actual power input by the motor 64 is essentially only thatwhich is necessary to perform the `actual cutting work on the worlcpiece28.

New referring to FIGS. 4, 5 :and 6, la vertical breaching |machine 65illustrating another embodiment of the invention is adapted to finishthe external surfaces oif a workpiece.

The breaching machine 65 is similar in arrangement te the aforementionedbreaching machine of FIGS. 1 to 3 'and has la pair of work stations 66and 68. A breach handling fixture 70 mounted to an upright frame 72 forvertical, reciprocal movement is associated with the work station 66 anda similar breach handling fixture is associated with the opposite workstation 68.

Frame 72 has a pair of lateral base portions 73 each supporting a platen74 associated with the work 4stations 66 and 68. A workpiece snppertingfixture 76 is mounted on each -of the platens 74 and is adapted toposition a workpiece 77 'having an unfinished external surface.

'Ilhe breach handling fixtures are similar to one another so that it isto be understood that a description of 'the breach handling fixture 70applies to the companion breach unit en the hidden side ef vframe 72 andassociated with work station 68. The breach handling fixture 70comprises a drive ram member 78 mounted for reciprocal movement betweenraised and lowered positions in -vertical guideways 80 of the frame 72.A surface breaching tool 82 `attached by `any conventional means to theram member 78 has a length such that in the raised position of the rarnmember 78, the lower cutting edges of the breaching tool 82 are spacedabove the workpiece 77. As the ram member 78 descends in a cuttingstroke, the cutting edges of the breaching tool 82 come into asurfacefinishing engagement with the workpiece 77 FIG. 5 illustrates howa drive rack 84 is carried en the inner side of each of the rams 78. Theracks 84 face one another and are in driving mesh with a pinion 86supported te frame 72 lfor rotation about a horizontal axis. A reversingmotor 88 having output through a reduction gear unit 90 provides asource of rotational power to the pinion 86. As the pinion 86 is rotatedin a counterclock- Wise direction as viewed in FIG. 5, the ram 78associa-ted with the werk station 68 is driven downwardly in a cuttingstroke while the ram 78 associated with the work station 66 is raised ina return stroke. At the end of the cutting stroke, the rotational output0f the motor is reversed so that the pinion 86 rotates in a reversedirection to drive the ram 78 -of the work station 66 in a ldownwardcutting stroke while lthe ram 78 ef the opposite work station 68 israised in a return stroke.

rIlhis alternate embodiment of the invention illustrates how thecounterbalanced ram arrangement of the invention can be incorporated inexternal `as Well yas internal breaching apparatus. The description ofthe preferred embodiments also illustrate how the power requirements forIbreaching apparatus can be reduced by employing this counterbalancedconfiguration.

New referring to FIGS. 4 and 6, the breaching machine 65 -has a breachtransfer means 92 which is described with reference -to the work station66. However it is to be understood that a similar breach transfer meansis mounted on the top orf `a column 94 extending upwardly from frame 72to accommodate the breaching tool `associated with the work station 68.The breach transfer means 92 is intended to transfer the breaching tool82 from its raised position above the platen 74 at the work station 66to a lateral position wherein the tool clears the work station and isreadily accessible to permit the installation of a replacement breachingtool.

The breach transfer means 92 inclfudes a horizontal track 96 having oneend directly above the work station 66 and its opposite end adjacent atransfer station 98. It will be understood that the transfer station 98is horizont-ally spaced from the work station 66. FIG. 4 illustrates thebreaching tool 82 in its raised position `above the work station 66,`and FIG. 6 illustrates the breaching tool 82 at the transfer station98. A carriage 100 mounted on the track 96 is movable along the track 96between a first position above the work station 66 and -a secondposition at the transfer station 98. A hydraulic cylinder 102 connectedto the carriage 100 is arranged to drive the carriage 100 between thetwo positions. The carriage 100 carries a pair of chucks 104 of anyconventional configuration which are engageable with a pair of handlingsections 106 forming a part of the breaching tool 82. A pair of hy-`draulic cylinders 108 mounted on carriage 100 actuate the chucks 104between lowered and raised positions.

In operation, the breaching tool `82 is transferred from its raisedposition above the work station 66 to the transfer station 98 byarranging the `carriage 100 above the work station 66, actuating thechucks 104 to a lowered position wherein they engage handling sections106, separating the breaching tool 82 from the ram 78, and then'actuating the hydraulic cylinder 102 to move the detached breachingtool 82 toward the transfer station 98. At the transfer station 98, thecylinders 108 iower the breaching tool 82 se that it is accessible -tothe operator. A replacement breaching tool is moved from the transferstation 98 te the work stati-on 66 by reversing the aforementionedprocedures.

Having thus described the invention, what is claimed as new is asfollows:

1. In a breaching machine, an upright supporting frame, a pair of breachram slides mounted on said supporting lframe for reciprocating movementalong a predetermined path between raised and lowered positions; abroaching tool supported by each olf said 4rarn slides; a rotary drivepinion member coupled to a source of rotary power, said rotary piniondrive member being connected in a torque transmitting relationship withcomplementary rack drive sections of each of said pair of broach ramslides and lbeing arranged to simultaneously move one of said broach ramslides from its lowered position toward its raised position.

2. The combination as defined in claim 1, wherein said ram slides arealternately movable between their respective raised and loweredpositions in a cutting stroke and in a non-cutting return stroke, andsaid broach ram slides move in a cutting stroke in a common direction.

3. The combination as defined in claim 2, wherein eac'h of said broachram slides are movably downwardly in a cutting stroke and upwardly in areturn stroke.

4. The combination as defined in claim 2, wherein said broach ram slidesand their associated broaching tools have a similar mass so that thetorque produced by the combined mass of one of the broach ram slides andits associated broaching tool and acting on the notary drive member iscounterbalanced by the torque developed by the combined mass of theopposite broach ram slide and its associated broaching tool.

5. The combination `as defined in claim 4, wherein said broach ramslides are movable in spaced parallel vertical paths.

6. The combination as defined in claim 1, including lbroadh handlingfixtures and meansniounted on said upright supporting frame, said meanscoacting with the movement of said Ibroach handling fixtures in acutting stroke and being operable to rotate an elongated broaching toolcarried by said broach handling fixture about its longitudinal axis asit progresses through a workpiece.

7. The combination as defined in claim 1, wherein said ram slides areadapted -to carry a broaching tool ifor finishing the internal surfaceof the workpiece. v

8. The combination as defined in claim 1, wherein said broach ram slidesare adapted to carry an elongated broaching tool `for cutting engagementwith the external surface of a workpiece.

References Cited UNITED STATES PATENTS

